Hadith 4:588

Narrated Abu Humaid As-Sa'idi:

The people asked, "O Allah's Apostle! How shall we (ask Allah to) send
blessings on you?" Allah's Apostle replied, "Say: O Allah! Send Your
Mercy on Muhammad and on his wives and on his off spring, as You sent
Your Mercy on Abraham's family; and send Your Blessings on Muhammad
and on his offspring, as You sent Your Blessings on Abraham's family,
for You are the Most Praise-worthy, the Most Glorious."